A21 kg chair initially at rest on a horizontal floor requires a 175 n horizontal force to set it in motion. once the chair is in motion, a 137 n horizontal force keeps it moving at a constant velocity. the acceleration of gravity is 9.81 m/s 2 . a) what is the coefficient of static friction between the chair and the floor?

Along wire of diameter 1 mm is submerged in an oil bath of temperature ∞ 31°c. the wire has an electrical resistance per unit length of 0.01 ω/m. if a current of 103 a flows through the wire and the convection coefficient is 500 w/m2·k, what is the steady-state temperature of the wire? from the time the current is applied, how long does it take for the wire to reach a temperature that is within 1°c of the steady-state value? the properties of the wire are 8000 kg/m3, 500 j/kg·k, and 20 w/m·k.